Local Sleep Spindle Density is Modulated by Motor Learning and Associated with Subsequent Sleep-Dependent Memory Consolidation

Martin Sjøgård, PhD

Massachusetts General Hospital – Fellow
SJOGARD_MARTIN poster

Scientific Abstract

Background

Evidence shows that motor-skill learning is consolidated by sleep spindles during non-rapid eye movement sleep stage 2 (N2), resulting in improved post-sleep performance. However, the macro-scale mechanism of where and how 1) learning induces changes in sleep spindles and 2) sleep spindles mediate memory consolidation, remains elusive.

Methods

We recruited 26 healthy participants and used combined electro- (EEG) and magnetoencephalography (MEG) to identify cortical regions that were involved in learning a finger tapping motor sequence task (MST). Then we utilized a novel combined EEG/MEG sleep spindle detector to detect sleep spindles during a 90 nap both independently of the task (baseline sleep) and directly after learning. We then analyzed whether learning induced a change in sleep spindle density (spindles per minute), whether these changes preferentially occurred in task-activated areas, and whether changes in sleep spindle density led to changes in overnap memory consolidation.

Results

Spindles were preferentially local, i.e. they were more likely to occur in regions which were active when learning the task. The degree of learning during training was associated with increased spindle density in task-related contralateral primary motor areas, while increased spindle density in bilateral primary and secondary motor and somatosensory areas was correlated with increased memory consolidation.

Discussion

The results show that the topography of sleep spindles is both task-relevant and relates to both learning and memory consolidation of the task in question.

Since spindle density changes related to learning and memory consolidation occurred in different brain areas, this may suggest functionally different roles for different areas with regards to spindle function.

Extending this study to patient populations with known impairments in sleep-dependent memory consolidation will be important in order to show whether these impairments are linked to breakdown in local spindle density modulation. It may also be of future interest to see how these modulations differ between different tasks involving different sensory/motor functions.

Live Zoom Session – March 9th

research Areas

Authors

Martin Sjøgård, PhD, Dimitrios Mylonas, PhD, Zhaoyue Shi, PhD, Sheraz Khan, PhD, Charmaine Demanuele, PhD, Lin Zhu1, PhD, Catherine Tocci, PhD, Robert Stickgold, PhD, Matti S. Hämäläinen, PhD, Dara S. Manoach, PhD

Principal Investigator

Dara S. Manoach, PhD